I made a ghetto star nut thang when I wanted to use a Try-All sloping stem on my trialtechs. I cut the 'mushroom' top off the screw in bolt, found an M5 nut with a small ridge around the bottom on Porter's dashboard, screwed the threaded bit into my forks with the nut on the bottom, put in a normal top cap and bolt and there we are. All info courtesy of Mr. Tarty Adam.